The present invention relates generally to equipment utilized in conjunction with operations performed in subterranean wells and, in an embodiment described herein, more particularly provides a plug apparatus having a fluid barrier.
It is known to construct a plug apparatus using a dispersible plug member, that is, a plug member or a portion thereof that is dissolvable or otherwise dispersible by contact with fluid. For example, the member may be initially isolated from contact with fluid and then, when it is desired to permit flow through the plug apparatus, fluid is placed in communication with the member, thereby dispersing the member. Such dispersible plug members have been constructed using compacted salt and sand mixtures, although other types of members may be utilized as well.
However, it is sometimes the case that the member may not be readily dispersible by contact with whatever fluid happens to be present in the well at the time it is desired to permit flow through the plug apparatus. For example, if the member is dispersible by dissolving a salt constituent thereof in fluid, and the fluid in the well is salt-saturated or oil-based, the salt constituent may not be readily dissolvable in the fluid. This situation may also occur where, for example, the member is dispersible by contact with a particular type of fluid, and that particular type of fluid is not present in the well, or is not otherwise available for contacting the member. For example, if the member is dispersible by a reaction with a particular type of fluid, and the fluid is not present in a tubular string attached to the plug apparatus, it may be difficult or inconvenient to provide that fluid for contact with the member at the time it is desired to permit flow through the plug apparatus.
Therefore, it would be very advantageous to provide a plug apparatus with the capability of dispersing its plug member, no matter the fluid present in the well at the time it is desired to permit flow through the plug apparatus. Additionally, it would be advantageous to provide a plug apparatus with the capability of transporting a fluid therewith which may be used to disperse its plug member. Furthermore, it would be advantageous to provide a fluid barrier which prevents contamination of fluid in a plug apparatus. Accordingly, objects of the present invention include providing such plug apparatus and fluid barriers.